switch many variable names in make-index; not disturbing as I'm currently the

only developper but is a bad thing to do.
improved handling of comments line during the parsing of the .sxd.

make-index

@@ -4,8 +4,7 @@
 # simplified version from the original C programm that parse the input.
 #
 # Usage: mk-idx.pl SRC
-#        SRC should be an .sxd file generated by latex during a first compilation
-#        of the file.
+#        SRC should be an .sxd file generated by the latex songs package
 #
 
 use warnings;
@@ -60,51 +59,57 @@ open( FILE, $file ) or die("unable to open $file");
 my @data = <FILE>;
 close( FILE );
 
-#process data
+# Process data
 my %table;
 
-my $type = shift @data; # first line determines the type of the index (AUTHOR or TITLE)
+# Get the type of the index. Not used but we have it.
+my $type = shift @data;
 
-if( $type =~ /AUTHOR/ )
-{
-    ;
-}
-elsif( $type =~ /TITLE/ )
-{
-    shift @data; # ignore the second line (in my test cases, it contains "%prefix" which should probably be ignored.
-}
+# Parse data and create the index table
+my $item;
+my $index;
+my $link;
+my $letter;
+my $ref;
 
 while( @data )
 {
-    my $item = shift @data;
+    $item = shift @data;
+    unless( $item =~ /^\s*%/ ) # ignore a line starting with %
+    {
 	chomp $item;
-    my $index = shift @data;
+	$index = shift @data;
 	chomp $index;
-    my $link = shift @data;
+	$link = shift @data;
 	chomp $link;
     
 	# Get the first letter or number of the current item
-    my $first_letter = get_first_letter $item;
-    
-    $table{$first_letter} = {} unless exists $table{$first_letter};
+	$letter = get_first_letter $item;
 
-    my $ref = { num => $index, link => $link };
+	# Create empty data index if needed
+	$table{$letter} = {} unless exists $table{$letter};
+    	$table{$letter}{$item} = [] unless exists $table{$letter}{$item};
 
-    $table{$first_letter}{$item} = [] unless exists $table{$first_letter}{$item};
+	# Create reference for the current item
+	$ref = { num => $index, link => $link };
     
-    push @{$table{$first_letter}{$item}}, $ref;
+	# Add the reference to the index
+	push @{$table{$letter}{$item}}, $ref;
+    }
 }
 
 # Create the index formated file
-foreach my $letter ( sort keys %table )
+my @refs;
+
+foreach $letter ( sort keys %table )
 {
     print '\begin{idxblock}{'.$letter."}\n";	
-    foreach my $item (sort keys %{$table{$letter}} )
+    foreach $item ( sort keys %{$table{$letter}} )
     {
 	print '\idxentry{';
 	print $item;
 	print '}{';
-	my @refs = @{$table{$letter}{$item}};
+	@refs = @{$table{$letter}{$item}};
 	print join ("\\\\", map { "\\hyperlink{$_->{link}}{$_->{num}}" } @refs);
 	print '}'."\n";
     }